Why do you want 64 gigs of ram? Are you actually using it for work related things? 32 is largely plenty for most “normal” people. Do you have 2 or 4 ram slots? And how many sticks currently? You could add another 16 gigs pretty cheaply. Or if you have two slots even 32 for cheap. Dual channel memory works fine with weird combos like that.
I’d personally upgrade CPU/RAM/Mobo if you find a good deal. Im also a chronic multi tasker and DESPISE CPU bottlenecks. Micro center has some good combos and I think you can upgrade the ram on them. I think their 7600x3D combo is pretty good and should be a nice upgrade over the 8700k. Or even the 7800x3D sometimes. It all depends on how much you want to spend.